diff --git a/ObsoleteFiles.inc b/ObsoleteFiles.inc
index 8a2c87b20645..70e6dcec50b1 100644
--- a/ObsoleteFiles.inc
+++ b/ObsoleteFiles.inc
@@ -51,6 +51,28 @@
 #   xargs -n1 | sort | uniq -d;
 # done
 
+# 20240511: move file system driver manuals to section four
+OLD_FILES+=usr/share/man/man5/autofs.5.gz
+OLD_FILES+=usr/share/man/man5/cd9660.5.gz
+OLD_FILES+=usr/share/man/man5/devfs.5.gz
+OLD_FILES+=usr/share/man/man5/ext2fs.5.gz
+OLD_FILES+=usr/share/man/man5/ext4fs.5.gz
+OLD_FILES+=usr/share/man/man5/fdescfs.5.gz
+OLD_FILES+=usr/share/man/man5/fusefs.5.gz
+OLD_FILES+=usr/share/man/man5/lindebugfs.5.gz
+OLD_FILES+=usr/share/man/man5/linprocfs.5.gz
+OLD_FILES+=usr/share/man/man5/linsysfs.5.gz
+OLD_FILES+=usr/share/man/man5/mqueuefs.5.gz
+OLD_FILES+=usr/share/man/man5/msdosfs.5.gz
+OLD_FILES+=usr/share/man/man5/msdos.5.gz
+OLD_FILES+=usr/share/man/man5/nullfs.5.gz
+OLD_FILES+=usr/share/man/man5/procfs.5.gz
+OLD_FILES+=usr/share/man/man5/smbfs.5.gz
+OLD_FILES+=usr/share/man/man5/tarfs.5.gz
+OLD_FILES+=usr/share/man/man5/tmpfs.5.gz
+OLD_FILES+=usr/share/man/man5/unionfs.5.gz
+OLD_FILES+=usr/share/man/man7/ffs.7.gz
+
 # 20240508: Remove remnants of portsnap(8)
 OLD_DIRS+=var/db/portsnap
 
diff --git a/tools/build/mk/OptionalObsoleteFiles.inc b/tools/build/mk/OptionalObsoleteFiles.inc
index 8898a405ea49..82227eef5d50 100644
--- a/tools/build/mk/OptionalObsoleteFiles.inc
+++ b/tools/build/mk/OptionalObsoleteFiles.inc
@@ -134,7 +134,7 @@ OLD_FILES+=etc/rc.d/autounmountd
 OLD_FILES+=usr/sbin/automount
 OLD_FILES+=usr/sbin/automountd
 OLD_FILES+=usr/sbin/autounmountd
-OLD_FILES+=usr/share/man/man5/autofs.5.gz
+OLD_FILES+=usr/share/man/man5/autofs.4.gz
 OLD_FILES+=usr/share/man/man5/auto_master.5.gz
 OLD_FILES+=usr/share/man/man8/automount.8.gz
 OLD_FILES+=usr/share/man/man8/automountd.8.gz